Anti-infective and antithrombogenic medical articles and method for their preparation

Abstract

An anti-infective medical article has chlorhexidine bulk distributed throughout a polyurethane base layer and may have a coating layer on the base layer. The coating layer may be chlorhexidine, an antibiotic, or an antithrombogenic agent permeated into the surface or it may be a polymeric surface layer having bulk distributed chlorhexidine laminated onto the base layer. The invention includes a method for preparing the article wherein a homogeneous melt of polymer and chlorhexidine is prepared by twin screw compounding and the melt is extruded to give a medical article having bulk distributed chlorhexidine. The article may then be laminated by dipping into a solution of chlorhexidine and a substantially hydrophilic polymer in a solvent.

What is claimed is: 
     
       1. A method for preparing a medical article comprising: a. extruding a first polymer having a water absorption of at least 0.6% by weight to obtain a shaped first polymer.   b. applying a laminated layer comprising a second polymer having a water absorption of at least 0.6% by weight and an antiinfective agent selected from the group consisting of a biguanide and silver sulfadiazine bulk distributed therein onto a surface of said shaped first polymer.   
     
     
       2. The method of claim 1 wherein said biguanide is chlorhexidine. 
     
     
       3. The method in accordance with claim 2 wherein said chlorhexidine is selected from the group consisting of chlorhexidine base and a salt thereof. 
     
     
       4. The method in accordance with claim 3 wherein said salt of chlorhexidine is selected from the group consisting of the hydrochloride, acetate and gluconate. 
     
     
       5. The method in accordance with claim 1 wherein said first and second polymers are selected from the group consisting of polyurethane, polyurethaneurea and siloxane-urethane block copolymer. 
     
     
       6. The method of claim 1 further comprising preparing a melt of said second polymer and said anti-infective agent by twin screw compounding and performing said applying step by dipping said shaped first polymer into said melt. 
     
     
       7. The method of claim 1 wherein said preparing step includes preparing a melt of said first polymer and said applying step includes preparing a homogeneous melt of said second polymer and said anti-infective agent and coextruding said melts. 
     
     
       8. The method of claim 1 further comprising preparing a solvent solution of said second polymer and said anti-infective agent and performing said applying step by dipping said shaped article into said solution. 
     
     
       9. The method in accordance with claim 1 further comprising permeating a quaternary ammonium salt into said laminated layer and reacting the permeated salt with a material selected from the group consisting of an antibiotic and an antithrombogenic agent.